Cutting tools in which a coating layer made from diamond is formed as a film on the surface of the base body are a well-known technology. Patent Document 1, for example, discloses tools such as a drill or an end mill in which a diamond layer is formed as a film on the surface of a base body having a rod shape. Moreover, Patent Document 2 discloses a wear-resistant tool member in which an Si-containing diamond-like carbon film is formed on the surface of a base body, and the carbon film has a graded composition in which the Si content ratio changes in the thickness direction of the coating layer.